[Rh2(phesp)2]: a Bulkier [Rh2(esp)2] Analog to Tune the Site‐Selectivity in Carbene C─H Insertion Reactions

Abstract [Rh 2 (phesp) 2 ], a new dirhodium(II) complex bearing a bulky bidentate bis‐carboxylate ligand, has been prepared in two steps from commercially available compounds. Its X‐ray structure revealed distinctive features with a strong distortion around the dirhodium(II) core, illustrated by important torsion angles of up to 9.0°. It has been evaluated as catalyst as a bulky version of the prominent [Rh 2 (esp) 2 ] complex in carbene C─H insertion reactions. [Rh 2 (phesp) 2 ] proved as active as [Rh 2 (esp) 2 ], and showed an intermediate selectivity between [Rh 2 (esp) 2 ] and bulky [Rh 2 (tpa) 4 ] in both intra‐ and intermolecular reactions with donor‐acceptor and acceptor‐acceptor diazo compounds, comprising challenging C(sp 3 )─H insertion into pentane.